Oni no Sentakuita, or the Devil’s Washboard is a magnificent spot on the famous Aoshima Island located in Miyazaki Prefecture. A “washboard” is a rough board that was used for washing clothes in an era when washing machines were not widespread. Called the “Devil’s Washboard”, a natural monument, where coastal rocks have become uneven, like the traditional washboard. At low tide, you can cross over to Aoshima Island by walking over the washboard without using a bridge!